1. Field of the Invention
The present invention relates to an endoscope having a distal end portion in which distal end sides of a light guide and an image guide are held.
2. Description of the Related Art
In conventional endoscopes, there is known one which forms an optical image inside a body on a solid-state image pickup device such as a CCD, and displays the image on a monitor, etc. Further, in this type of endoscope, in order to reduce a diameter of a distal end portion of an insertion portion, there is known an endoscope in which the solid-state image pickup device is arranged in an operation portion and an optical image formed by an objective optical system arranged in the distal end portion is conducted to the operation portion through an image guide, and the optical image formed at an emission end of the image guide is produced on the solid-state image pickup device in the operation portion through a relay lens system.
Here, it is general that this type of endoscope has a light guide for transmitting illumination light to the distal end portion in addition to the image guide, and distal end sides of the image guide and the light guide are held by being individually inserted into through holes provided to be close to each other at a distal end rigid portion (see for example Japanese Patent Laid-Open Publication No. 2009-28109).
Incidentally, in an ultrasound endoscope provided with an ultrasound observation section at a distal end portion in addition to an optical observation portion as described above, it is general that a distal end rigid portion made of resin is adopted for the purpose of securing high insulation property.